Android:alertdialog中通过样式显示的消息字体大小 [英] Android: message font size in alertdialog through styles

问题描述

我正在尝试通过样式更改警报对话框中消息的字体大小，但无法使其正常工作.有很多答案描述了如何执行此操作，但是我发现它们几乎都是以编程方式完成的.我想只使用一次样式，而不是使用每个新的Alertdialog.

I'm trying to change font size of message in alert dialog through styles but I can't make it work. There is a lot of answers describing how to do this but almost all of them I found do it programmatically. I want to do this once in styles, not with every new alertdialog.

到目前为止我所做的:

在\AndroidSDK\platforms\android-23\data\res\layout\alert_dialog.xml中，我看到显示消息的TextView:

In \AndroidSDK\platforms\android-23\data\res\layout\alert_dialog.xml I see the TextView that is showing the message:

<TextView android:id="@+id/message"
    style="?android:attr/textAppearanceMedium"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="5dip" />

在\AndroidSDK\platforms\android-23\data\res\values\themes.xml中，我看到textAppearanceMedium属性的值是@style/TextAppearance.Medium.

In \AndroidSDK\platforms\android-23\data\res\values\themes.xml I see that the value of textAppearanceMedium attribute is @style/TextAppearance.Medium.

我创建了以下样式，其父样式为TextAppearance.AppCompat.Medium.然后将此样式应用于AlertDialog样式的android:textAppearanceMedium属性，如下所示:

I've created a following style of which the parent is TextAppearance.AppCompat.Medium. This style is then applied to android:textAppearanceMedium attribute of AlertDialog's style as follows:

<style name="Theme.My" parent="Theme.AppCompat.Light.NoActionBar.FullScreen">
    <item name="android:alertDialogTheme">@style/Theme.My.AlertDialog</item>
</style>

<style name="Theme.My.AlertDialog" parent="Theme.AppCompat.Light.Dialog.Alert">
    <item name="android:textAppearanceMedium">@style/MyTextAppearanceMedium</item>
</style>

<style name="MyTextAppearanceMedium" parent="TextAppearance.AppCompat.Medium">
    <item name="android:textSize">24sp</item>
</style>

...但是字体大小不会改变.怎么了?

...but the font size won't change. What's wrong?

我正在使用AppCompat支持库，最小SDK 16，目标SDK 23.

I'm using AppCompat support lib, min SDK 16, target SDK 23.

谢谢.

推荐答案

AlertDialog使用主题属性?android:attr/textAppearanceMedium"作为对话框内容，直到材料主题"为止.

AlertDialog was using the theme attribute ?android:attr/textAppearanceMedium" for dialog content until Material Theme.

如果您查看AlertDialog的源代码，它将使用AlertController来管理AlertDialog.在AlertDialog构造函数中，我们有:

If you look at the source code of AlertDialog it uses an AlertControllerto manage the AlertDialog. In AlertDialog constructor we have this :

 TypedArray a = context.obtainStyledAttributes(null,
             com.android.internal.R.styleable.AlertDialog,
             com.android.internal.R.attr.alertDialogStyle, 0);

     mAlertDialogLayout = a.getResourceId(com.android.internal.R.styleable.AlertDialog_layout,
             com.android.internal.R.layout.alert_dialog);

我们可以看到AlertDialog的布局来自declare-styleable name=AlertDialog中声明的属性" layout "，并在主题级别的属性alertDialogStyle中定义.

We can see that the layout for the AlertDialogcomes from an attribute called "layout" declared in declare-styleable name=AlertDialog and defined at theme level in the attribute alertDialogStyle.

知道，在Material主题中查看alertDialogStyle，我们得到了这个
<item name="alertDialogStyle">@style/AlertDialog.Material</item>

Know, looking at alertDialogStyle in Material theme we got this
<item name="alertDialogStyle">@style/AlertDialog.Material</item>

，在 Alert.Dialog.Material 处，我们得到了<item name="layout">@layout/alert_dialog_material</item>

它使用的是 alert_dialog_material ，而不是 alert_dialog .

在 alert_dialog_material 中，我们具有相同的TextView

In alert_dialog_material we have the same TextView

<TextView android:id="@+id/message"
                      style="@style/TextAppearance.Material.Subhead"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"
                      android:paddingStart="@dimen/alert_dialog_padding_material"
                      android:paddingTop="@dimen/alert_dialog_padding_top_material"
                      android:paddingEnd="@dimen/alert_dialog_padding_material" />

但是样式指向本地主题而不是?android:attr/textAppearanceMedium，这就是为什么您不能像以前那样对消息进行样式设置.

but the style points to a local theme instead of ?android:attr/textAppearanceMedium and that's why you can't style the message like before.

解决方案1:

我们只能以编程方式执行此操作.使用对话框中的窗口获取TextView并设置所需的外观:

We can only do this programmatically. Get the TextViewusing the window from the Dialog and set the appearance you want:

android.support.v7.app.AlertDialog d = builder.show();
TextView tv = (TextView)d.getWindow().findViewById(android.R.id.message);

解决方案2:

为使其更加灵活，我们可以在attrs.xml

To make it more flexible we can define an attribute in attrs.xml

<resources>
    <attr name="dialogMessageStyle" format="reference"/>
</resources>

在主题中定义属性:

<style name="MyStyle" ...>
    <item name="dialogMessageStyle">@style/AlertDialogMessageAppearance</item>
</style>

并使用以下代码进行设置:

And set it in code using:

 TextView tv = (TextView)d.getWindow().findViewById(android.R.id.message);
            TypedArray a = getTheme().obtainStyledAttributes(new int[]{R.attr.dialogMessageStyle});
            tv.setTextAppearance(DialogActivity.this,a.getResourceId(0,0));

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